Hydrophobing additive

ABSTRACT

Hydrophobicizing agents which are easily admixed with construction chemical products are prepared by providing a solution of a protective colloid and adding thereto a fatty acid compound sensitive to high pH environments, optionally, a hydrophobicizing organosilicon compound, and drying the resulting aqueous mixture.

CROSS-REFERENCE TO RELATED APPLICATION

This application is the U.S. national phase of PCT Appln. No.PCT/EP04/005154 filed May 13, 2004, which claims priority to Germanapplication 103 23 205.2 filed May 22, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a hydrophobicizing, water-redispersibleadditive based on fatty acids and their derivatives and, whereappropriate, organosilicon compounds, to a process for theirpreparation, and to their use.

2. Description of the Related Art

Lime- or cement-bound construction materials, such as renders,trowelling compounds and construction adhesives need protection from theeffects of weathering. Rain or snow causes wetting throughout theconstruction materials, for example the external render, as a result ofcapillary action, and this can lead to irreversible damage to thebuilding. Hydrophobicization of the construction materials is a familiarand longstanding method of preventing this.

DE-A 2341085, EP-A 342609 and EP-A 717016 disclose that fatty acidesters may be added as hydrophobicizing agents to lime- or cement-boundrenders. A frequent disadvantage here is specifically thehydrophobicizing character of these additives. If dry renders in whichthese hydrophobicizing agents are present are mixed with water theresult is then poor wetting of the materials, and therefore markedlyimpaired processability.

Water-redispersible powders based on homo- or copolymers ofethylenically unsaturated monomers are used in the construction sectoras binders, in combination with hydraulically setting binders, such ascement. By way of example, these are used in construction adhesives,renders, mortars, and paints to improve mechanical strength andadhesion. WO-A 95/20627, WO-A 02/31036 and DE-A 10233933 disclose thatadditives with hydrophobicizing action, such as organosilicon compoundsand fatty acid esters, may be used as a constituent of redispersionpowders in dry mortars. The problems of poor wettability andprocessability are thus circumvented. However, the hydrophobicizingeffect is dependent on the proportion of the hydrophobicizing agent inthe redispersion powder and cannot therefore be varied as desired.

EP-A 1193287 recommends powder compositions with at least one fatty acidester for hydrophobicizing construction material compositions. To thisend, the fatty acid ester is applied as described immediately above as aconstituent of a redispersible polymer powder, with precisely thedisadvantages described. Another embodiment proposes using thehydrophobicizing agent as dry substance, applied to an inert, inorganiccarrier material, such as silica. A disadvantage here is that an inertsubstance is therefore introduced into the construction materialcomposition, and this can have an adverse effect on its mechanicalstrength.

SUMMARY OF THE INVENTION

It was therefore an object to provide a hydrophobicizing additive whichis intended for construction material compositions and which can beprocessed as a constituent of a dry mortar formulation without thedifficulties mentioned, and which can be metered independently of otherconstituents of the formulation, and which does not reduce mechanicalstrength by introducing an inert substance.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The invention therefore provides a hydrophobicizing water-redispersibleadditive based on fatty acids and their derivatives comprising

-   a) from 30 to 95% by weight of one or more water-soluble protective    colloids,-   b) from 5 to 70% by weight of one or more compounds from the group    consisting of    -   b1) fatty acids and fatty acid derivatives which, under alkaline        conditions, liberate fatty acid or liberate the corresponding        fatty acid anion,    -   where appropriate in combination with    -   b2) one or more organosilicon compounds, and-   c) from 0 to 30% by weight of antiblocking agents, the data in % by    weight being based on the total weight of the additive and giving    100% by weight in total.

Materials suitable as component b1) are generally fatty acids and fattyacid derivatives which under alkaline conditions, preferably pH>8,liberate fatty acids or liberate the corresponding fatty acid anion.Preference is given to fatty acid compounds from the group of the fattyacids having from 8 to 22 carbon atoms, their metal soaps, their amides,and also their esters with monohydric alcohols having from 1 to 14carbon atoms, with glycol, with polyglycol, with polyalkylene glycol,with glycerol, with mono-, di- or triethanolamine, with monosaccharides.

Suitable fatty acids are branched and unbranched, saturated andunsaturated fatty acids each having from 8 to 22 carbon atoms. Examplesare lauric acid (n-dodecanoic acid), myristic acid (n-tetradecanoicacid), palmitic acid (n-hexadecanoic acid), stearic acid (n-octadecanoicacid), and also oleic acid (9-dodecenoic acid).

Suitable metal soaps are those of the abovementioned fatty acids withmetals of 1^(st) to 3^(rd) main group or 2^(nd) transition group of thePTE, or else with ammonium groupings NX₄ ⁺, where X is identical ordifferent and is H, a C₁-C₈-alkyl radical, or a C₁-C₈-hydroxyalkylradical. Preference is given to metal soaps with lithium, sodium,potassium, magnesium, calcium, aluminium, zinc, and with the ammoniumgroupings.

Suitable fatty acid amides are the fatty acid amides obtainable withmono- or diethanolamine and with the abovementioned C₈-C₂₂ fatty acids.

Fatty acid esters suitable as component b1) are the C₁-C₁₄-alkyl estersand C₁-C₁₄-alkylaryl esters of the C₈-C₂₂ fatty acids mentioned,preferably methyl, ethyl, propyl, butyl, ethylhexyl esters, and also thebenzyl ester.

Other suitable fatty acid esters are the mono-, di- and polyglycolesters of the C₈-C₂₂ fatty acids.

Further suitable fatty acid esters are the mono- and diesters ofpolyglycols and/or of polyalkylene glycols having up to 20 oxyalkyleneunits, for example polyethylene glycol and polypropylene glycol.

Other suitable fatty acid esters are the mono-, di- and triesters ofglycerol with the C₈-C₂₂ fatty acids mentioned, and also the mono-, di-and triesters of mono-, di- and triethanolamine with the C₈-C₂₂ fattyacids mentioned.

The fatty acid esters of sorbitol and mannitol are also suitable.

Particular preference is given to the C₁-C₁₄-alkyl esters and -alkylarylesters of lauric acid and of oleic acid, mono- and diesters of glycolwith lauric acid and with oleic acid, and also the mono-, di- andtriesters of glycerol with lauric acid and with oleic acid.

The specified fatty acids and fatty acid derivatives may be used aloneor in a mixture. The amount generally used of component b1) is from 5 to70% by weight, preferably from 10 to 40% by weight, based in each caseon the total weight of the hydrophobicizing additive.

Where appropriate, the specified fatty acids and fatty acid derivativesmay be used with organosilicon compounds b2). Suitable organosiliconcompounds are the silicic esters Si (OR′)₄, tetraorganosilanes SiR₄,organoorganoxysilanes SiR_(n)(OR′)_(4-n), where n=from 1 to 3,polysilanes preferably of the general formula R₃Si(SiR₂)_(n)SiR₃, wheren=from 0 to 500, organosilanols SiR_(n)(OH)_(4-n), di-, oligo- andpolysiloxanes composed of units of the general formulaR_(c)H_(d)Si(OR′)_(e)(OH)_(f)O_((4-c-d-e-f)/2), where c=from 0 to 3,d=from 0 to 1, e=from 0 to 3, f=from 0 to 3 and c+d+e+f is not more than3.5 per unit, where each R is identical or different and is a branchedor unbranched alkyl radical having from 1 to 22 carbon atoms, cycloalkylradical having from 3 to 10 carbon atoms, alkenyl radical having from 2to 4 carbon atoms, or else aryl, aralkyl or alkylaryl radical havingfrom 6 to 18 carbon atoms, and R′ is identical or different alkylradicals and alkoxyalkylene radicals each having from 1 to 4 carbonatoms, preferably methyl or ethyl, and where the radicals R and R′ mayalso have substitution by halogens, such as Cl, by ether, thioether,ester, amide, nitrile, hydroxy, amine, carboxy, sulfonic acid,carboxylic anhydride or carbonyl groups, and where in the case of thepolysilanes R can also have the meaning OR′. Other suitable materialsare carbosilanes, polycarbosilanes, carbosiloxanes, polycarbosiloxanes,polysilylenedisiloxanes.

As component b2), preference is given to tetramethoxysilane,tetraethoxysilane, methyltripropoxysilane,methyltri(ethoxyethoxy)silane, vinyltri(methoxyethoxy)silane,(meth)acryloxypropyltrimethoxysilane,(meth)acryloxypropyltriethoxysilane, γ-chloropropyltriethoxysilane,β-nitriloethyltriethoxysilane, γ-mercaptopropyltrimethoxysilane,γ-mercaptopropyltriethoxysilane, phenyltriethoxysilane,isooctyltriethoxysilane, n-octyltriethoxysilane,hexadecyltriethoxysilane, dipropyldiethoxysilane,methylphenyldiethoxysilane, diphenyldimethoxysilane,methylvinyltri(ethoxyethoxy)silane, tetramethyldiethoxydisilane,trimethyltrimethoxydisilane, trimethyltriethoxydisilane,dimethyltetramethoxydisilane, dimethyltetraethoxydisilane,methylhydropolysiloxanes end-capped with trimethylsiloxy groups,copolymers end-capped with trimethylsiloxy groups and composed ofdimethylsiloxane units and methylhydrosiloxane units,dimethylpolysiloxanes, and also dimethylpolysiloxanes whose terminalunits have Si—OH groups. Most preference is given to theorganoorganoxysilanes SiR_(n)(OR′)_(4-n), where n=from 1 to 3, inparticular isooctyltriethoxysilane, n-octyltriethoxysilane,hexadecyltriethoxysilane.

The organosilicon compounds b2) may be used alone or in a mixture. Theamount preferably used of component b2) is from 0.1 to 20% by weight,particularly preferably from 1 to 10% by weight, based in each case onthe total weight of the hydrophobicizing additives The preparation ofthe organosilicon compounds mentioned may use processes as described inNoll, Chemie und Technologie der Silicone [Chemistry and technology ofthe silicones], 2nd edition 1968, Weinheim, and in Houben-Weyl, Methodender organischen Chemie [Methods of organic chemistry], volume E20, GeorgThieme Verlag, Stuttgart (1987).

Suitable protective colloids are partially hydrolyzed and fullyhydrolyzed polyvinyl alcohols; polyvinylpyrrolidones; polyvinyl acetals;polysaccharides in water-soluble form, such as starches (amylose andamylopectin), celluloses and their carboxymethyl, methyl, hydroxyethyl,hydroxypropyl derivatives; proteins, such as casein or caseinate, soyaprotein, gelatin; lignosulfonates; synthetic polymers, such aspoly(meth)acrylic acid, copolymers of (meth)acrylates withcarboxy-functional comonomer units, poly(meth)acrylamide,polyvinylsulfonic acids and their water-soluble copolymers;melamine-formaldehydesulfonates, naphthalene-formaldehydesulfonates,styrene-maleic acid copolymers and vinyl ether-maleic acid copolymers.

Preference is given to partially hydrolyzed or fully hydrolyzedpolyvinyl alcohols with a degree of hydrolysis of from 80 to 100 mol %,in particular partially hydrolyzed polyvinyl alcohols with a degree ofhydrolysis of from 80 to 95 mol % and with a Höppler viscosity of from 1to 30 mPas, preferably from 3 to 15 mPas, in 4% strength aqueoussolution (Höppler method at 20° C., DIN 53015).

Preference is also given to partially hydrolyzed or fully hydrolyzed,hydrophobically modified polyvinyl alcohols with a degree of hydrolysisof from 80 to 100 mol % and with a Höppler viscosity of from 1 to 30mPas, preferably from 3 to 15 mPas, in 4% strength aqueous solution.Examples of these are partially hydrolyzed copolymers of vinyl acetatewith hydrophobic comonomers, such as isopropenyl acetate, vinylpivalate, vinyl ethylhexanoate, vinyl esters of saturated alpha-branchedmono-carboxylic acids having 5 or from 9 to 11 carbon atoms, dialkylmaleates and dialkyl fumarates, such as diisopropyl maleate anddiisopropyl fumarate, vinyl chloride, vinyl alkyl ethers such as vinylbutyl ether, alpha-olefins having from 2 to 12 carbon atoms, such asethene, propene and decene. The proportion of the hydrophobic units ispreferably from 0.1 to 10% by weight, based on the total weight of thepartially or fully hydrolyzed polyvinyl alcohol. Particular preferenceis given to partially hydrolyzed or fully hydrolyzed copolymers of vinylacetate with isopropenyl acetate with a degree of hydrolysis of from 95to 100 mol %. It is also possible to use mixtures of the polyvinylalcohols mentioned.

Most preference is given to partially hydrolyzed polyvinyl alcohols witha degree of hydrolysis of from 85 to 94 mol % and with a Höpplerviscosity of from 3 to 15 mPas in 4% strength aqueous solution (Höpplermethod at 20° C., DIN 53015), and also to partially hydrolyzed or fullyhydrolyzed polymers of vinyl acetate with isopropenyl acetate with adegree of hydrolysis of from 95 to 100 mol %. The polyvinyl alcoholsmentioned are obtainable by processes known to the person skilled in theart.

To prepare the hydrophobicizing additives, component b) is stirred intoan aqueous solution of the protective colloid a) and dried, for exampleby means of fluidized-bed drying, thin-film drying (drum drying), freezedrying or spray drying. The aqueous mixtures are preferably spray-dried.The spray drying takes place in conventional spray-drying systems, andthe atomization method here may use single-, twin- or multifluidnozzles, or a rotating disc. The discharge temperature is generallyselected in the range from 45 to 120° C., preferably from 60 to 90° C.,depending on the system, the Tg of the resin and the desired degree ofdrying.

The total amount of protective colloid is to be from 30 to 95% byweight, based on the total weight of the hydrophobicizing additive; itis preferable to use from 40 to 70% by weight, based on the total weightof the hydrophobicizing additive.

A content of up to 1.5% by weight of antifoam, based on the proportionof component b), has often proven successful during the sprayingprocess. In order to increase storage capability by improving resistanceto blocking, an antiblocking agent (anticaking agent) may be added tothe material, preferably at from 1 to 30% by weight, based on the totalweight of the hydrophobic additive. Examples of antiblocking agents arecalcium carbonate, magnesium carbonate, talc, gypsum, silica, kaolins,silicates with particle sizes preferably in the range from 10 nm to 10μm.

The hydrophobicizing additives may be used in a variety of applicationsectors, for example in construction chemistry products, whereappropriate in association with hydraulically setting binders, such ascements (Portland, alumina, pozzolanic, slag, magnesia, phosphatecement) or waterglass, or in gypsum-containing compositions, inlime-containing compositions, or in cement-free and polymer-boundcompositions, for the production of construction adhesives, inparticular tile adhesives and exterior insulation system adhesives,renders, trowelling compounds, floor-filling compositions, levellingcompositions, sealing slurries, jointing mortars and paints. The amountgenerally added of the hydrophobicizing additive is from 0.1 to 10% byweight, based on the total weight of the mix to be hydrophobicized(without water content).

The hydrophobicizing additives are particularly advantageously used inthe abovementioned application sectors in combination withwater-redispersible polymer powders. The polymer powders termedwater-redispersible polymer powders are those which in water break downagain to give the primary particles, which are then dispersed in thewater. Suitable polymers are those based on one or more monomers fromthe group consisting of vinyl esters of unbranched or branchedalkanecarboxylic acids having from 1 to 15 carbon atoms, methacrylicesters and acrylic esters of alcohols having from 1 to 15 carbon atoms,vinylaromatics, olefins, dienes and vinyl halides. It is also possibleto use mixtures of the polymers mentioned. In the applications mentionedit is preferable to use from 1 to 50% by weight of water-redispersiblepolymer powders, based on the total weight of the mix (without watercontent).

Preferred vinyl esters are vinyl acetate, vinyl propionate, vinylbutyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate,vinyl pivalate and vinyl esters of alpha-branched monocarboxylic acidshaving from 5 to 11 carbon atoms, e.g. VeoVa5®, VeoVa9®, VeoVa10® orVeoVa11® (tradename of Shell). Preferred methacrylic esters or acrylicesters are methyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, propyl acrylate, propyl methacrylate, n-butyl acrylate,n-butyl methacrylate, 2-ethylhexyl acrylate. Preferred vinylaromaticsare styrene, methylstyrene and vinyl-toluene. Preferred vinyl halide isvinyl chloride. The preferred olefins are ethylene, propylene, and thepreferred dienes are 1,3-butadiene and isoprene.

Where appropriate, the polymers may also contain from 0.1 to 10% byweight, based on the total weight of the polymer, of functionalcomonomer units from the group of the ethylenically unsaturated mono- ordicarboxylic acids, such as acrylic acid; that of the ethylenicallyunsaturated carboxamides, such as (meth)acrylamide, or from the group ofthe ethylenically unsaturated sulfonic acids and their salts, preferablyvinylsulfonic acid, or from the group of the ethylenicallypolyunsaturated comonomers, such as divinyl adipate, diallyl maleate,allyl methacrylate or triallyl cyanurate, and/or from the group of theN-methylol(meth)acrylamides and their ethers, such as isobutoxy ether orn-butoxy ether.

Particularly preferred polymers are those listed below, the data inpercent by weight giving a total of 100% by weight, where appropriatewith the proportion of functional comonomer units:

From the group of the vinyl ester polymers, vinyl acetate polymers,vinyl acetate-ethylene copolymers with an ethylene content of from 1 to60% by weight; vinyl ester-ethylene-vinyl chloride copolymers with anethylene content of from 1 to 40% by weight and with a vinyl chloridecontent of from 20 to 90% by weight; vinyl acetate copolymers with from1 to 50% by weight of one or more copolymerizable vinyl esters, such asvinyl laurate, vinyl pivalate, vinyl esters of an alpha-branchedcarboxylic acid, in particular vinyl versatates (VeoVa9^(R),VeoVa10^(R), VeoVa11^(R)), which, where appropriate, also contain from 1to 40% by weight of ethylene; vinyl acetate-acrylate copolymers withfrom 1 to 60% by weight of acrylate, in particular n-butyl acrylate or2-ethylhexyl acrylate, which, where appropriate, also contain from 1 to40% by weight of ethylene.

From the group of the (meth)acrylic ester polymers, polymers of n-butylacrylate or 2-ethylhexyl acrylate; copolymers of methyl methacrylatewith n-butyl acrylate and/or 2-ethylhexyl acrylate, copolymers of methylmethacrylate with 1,3-butadiene.

From the group of the vinyl chloride polymers, besides theabovementioned vinyl ester-vinyl chloride-ethylene copolymers, vinylchloride-ethylene copolymers and vinyl chloride-acrylate copolymers.

From the group of the styrene polymers, styrene-butadiene co-polymersand styrene-acrylate copolymers, such as styrene-n-butyl acrylate orstyrene-2-ethylhexyl acrylate, each with a styrene content of from 10 to70% by weight.

The polymers are prepared in a manner known per se, preferably by theemulsion polymerization process. Use may be made either ofemulsifier-stabilized dispersions or of dispersions stabilized withprotective colloid, such as polyvinyl alcohol. To prepare thewater-redispersible polymer powders, the resultant polymer dispersion isdried. The method of drying may be spray drying, freeze drying, orcoagulation of the dispersion followed by fluidized-bed drying. Spraydrying is preferred.

The hydrophobicizing additives are used to provide hydrophobicizingagents which may be metered independently of other constituents of theformulation. Because the additive is redispersible, the problemsoccurring hitherto in the processing of hydrophobic additives areeliminated. The content of protective colloid is also advantageous,because in particular polyvinyl alcohol also acts as a binder and thusimproves the mechanical strength of construction materials.

The examples below provide further illustration of the invention:

Example 1

10 parts by weight of methyl laurate were mixed with a mixture composedof 10 parts by weight of a 30% strength by weight aqueous solution of apolyvinyl alcohol with a Höppler viscosity of 13 mPas and with a degreeof hydrolysis of 88 mol % and 90 parts by weight of a 30% strength byweight aqueous solution of a polyvinyl alcohol with a Höppler viscosityof 4 mPas and with a degree of hydrolysis of 88 mol %, and sprayed,using a twin-fluid nozzle. The dry powder was blended with 15 parts byweight of an antiblocking agent based on calcium magnesium carbonate.

Example 2

10 parts by weight of glycol monolaurate and 5 parts by weight ofisooctyltriethoxysilane were mixed with a mixture composed of 10 partsby weight of a 30% strength by weight aqueous solution of a polyvinylalcohol with a Höppler viscosity of 13 mPas and with a degree ofhydrolysis of 88 mol % and 90 parts by weight of a 30% strength byweight aqueous solution of a polyvinyl alcohol with a Höppler viscosityof 4 mPas and with a degree of hydrolysis of 88 mol %, and sprayed,using a twin-fluid nozzle. The dry powder was blended with 15 parts byweight of an antiblocking agent based on calcium magnesium carbonate.

Example 3

20 parts by weight of propylene glycol dilaurate were mixed with 100parts by weight of a 30% strength by weight aqueous solution of apolyvinyl alcohol with a Höppler viscosity of 4 mPas and with a degreeof hydrolysis with 88 mol %, and sprayed, using a twin-fluid nozzle. Thedry powder was blended with 15 parts by weight of an antiblocking agentbased on calcium magnesium carbonate.

Comparative Example 4

100 parts by weight of a 30% strength by weight aqueous solution of apolyvinyl alcohol with a Höppler viscosity of 4 mPas and with a degreeof hydrolysis of 88 mol % were sprayed, using a twin-fluid nozzle. Thedry powder was blended with 15 parts by weight of an antiblocking agentbased on calcium magnesium carbonate.

Performance Test:

The hydrophobicizing action of the substances mentioned was determined,using a dry mortar with the following composition:

280.0 parts by Dyckerhoff white cement weight 500.0 parts by Quartz sand(0.1-0.4 mm) weight 190.0 parts by Juraperle MHS weight 1.5 parts byTylose MH 10001 P4 weight 4 parts by Hydrophobicizing agent weight 24parts by Water for 100 parts by weight of dry mixture weightWater Absorption Test:

A mortar layer of thickness 4 mm was applied by troweling onto expandedconcrete. The specimens were sealed at the edges and immersed in waterwith the mortar layer downward. Water absorption in kg/m²h^(0.5) wasdetermined from the weight increase per square meter and the time.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 C. Ex. 4 0.5 0.05 0.34 1.8

1. A process for preparation of a hydrophobicizing, water-redispersibleadditive based on fatty acids and their derivatives comprising admixinga) from 30 to 95% by weight of one or more water-soluble protectivecolloids, b1) from 5 to 70% by weight of one or more compounds selectedfrom the group consisting of fatty acids and fatty acid derivatives,which under alkaline conditions liberate fatty acid or liberate thecorresponding fatty acid anion, b2) optionally, one or moreorganosilicon compounds, and c) from 0 to 30% by weight of antiblockingagents, the data in % by weight being based on the total weight of theadditive and totaling 100% by weight, wherein said step of admixingcomprises stirring components b1) and b2) into an aqueous solution ofthe protective colloid a) followed by drying to form a powdery driedadditive.
 2. The process of claim 1, wherein one or more components b1)are selected from the group consisting of fatty acids having from 8 to22 carbon atoms, their metal soaps, their amides, and their esters withmonohydric alcohols having from 1 to 14 carbon atoms, with glycol, withpolyglycol, with polyalkylene glycol, with glycerol, with mono-, di- ortriethanolamine, with monosaccharides.
 3. The process of claim 1,wherein the component b1) comprises one or more fatty acid estersselected from the group consisting of C₁-C₁₄-alkyl esters andC₇₋₁₄-alkylaryl esters of branched and unbranched, saturated andunsaturated fatty acids having from 8 to 22 carbon atoms; mono-, di-,and polyglycol esters of branched and unbranched, saturated andunsaturated fatty acids having from 8 to 22 carbon atoms; mono- anddiesters of polyglycols and polyalkylene glycols having up to 20oxyalkylene units, with branched and unbranched, saturated andunsaturated fatty acids having from 8 to 22 carbon atoms; mono-, di- andtriesters of glycerol with branched and unbranched, saturated andunsaturated fatty acids having from 8 to 22 carbon atoms; mono-, di- andtriesters of mono-, di- and triethanolamine with branched andunbranched, saturated and unsaturated fatty acids having from 8 to 22carbon atoms; and esters of sorbitol and of mannitol with branched andunbranched, saturated and unsaturated fatty acids having from 8 to 22carbon atoms.
 4. The process of claim 1, wherein component b2) comprisesone or more organosilicon compounds selected from the group consistingof silicic esters, silanes, polysilanes, organosilanols, disiloxanes,oligosiloxanes, polysiloxanes, carbosilanes, polycarbosilanes,carbosiloxanes, polycarbosiloxanes, and polysilylenedisiloxanes.
 5. Theprocess of claim 1, wherein component b2) comprises one or moreorganosilicon compounds selected from the group consisting of silicicesters Si(OR′)₄, tetraorganosilanes SiR₄, organoorganoxysilanesSiR_(n)(OR′)_(4-n) where n=from 1 to 3, polysilanes of the formulaR₃Si(SiR₂)_(n)SiR₃ where n=from 0 to 500, organosilanolsSiR_(n)(OH)_(4-n), and di-, oligo- and polysiloxanes composed of unitsof the formula R_(c)H_(d)Si(OR″)_(e)(OH)_(f)O_((4-c-d-e-f)/2) wherec=from 0 to 3, d=from 0 to 1, e=from 0 to 3, f=from 0 to 3 and c+d+e+fis not more than 3.5 per unit, where each R is identical or differentand is a branched or unbranched alkyl radical having from 1 to 22 carbonatoms, a cycloalkyl radical having from 3 to 10 carbon atoms, alkenylradical having from 2 to 4 carbon atoms, or an aryl, aralkyl oralkylaryl radical having from 6 to 18 carbon atoms, and R′ is identicalor different and is an alkyl radical or alkoxyalkylene radical eachhaving from 1 to 4 carbon atoms, and where the radicals R and R′ mayalso be substituted by halogen, by ether, thioether, ester, amide,nitrile, hydroxy, amine, carboxy, sulfonic acid, carboxylic anhydride orcarbonyl groups, and where in the case of the polysilanes, R isoptionally OR′.
 6. The process of claim 1, wherein component a)comprises one or more protective colloids selected from the groupconsisting of partially hydrolyzed and fully hydrolyzed polyvinylalcohols with a degree of hydrolysis of from 80 to 100 mol % and with aHöppler viscosity of from 1 to 30 mPas in 4% strength aqueous solution,and partially hydrolyzed and fully hydrolyzed, hydrophobically modifiedpolyvinyl alcohols with a degree of hydrolysis of from 80 to 100 mol %and with a Höppler viscosity of from 1 to 30 mPas in 4% strength aqueoussolution.
 7. The process of claim 6, wherein at least onehydrophobically modified polyvinyl alcohol is present, and comprisespartially hydrolyzed or fully hydrolyzed copolymers of vinyl acetatewith one or more hydrophobic comonomers selected from the groupconsisting of isopropenyl acetate, vinyl pivalate, vinyl ethylhexanoate,vinyl esters of saturated alpha-branched monocarboxylic acids having 5and from 9 to 11 carbon atoms, dialkyl maleates and dialkyl fumarates,vinyl chloride, vinyl alkyl ethers, and alpha-olefins having from 2 to12 carbon atoms.
 8. The process of claim 6, wherein component a)comprises one or more protective colloids selected from the groupconsisting of partially hydrolyzed polyvinyl alcohols with a degree ofhydrolysis of from 85 to 94 mol % and a Höppler viscosity of from 3 to15 mPas in 4% strength aqueous solution, and partially hydrolyzed andfully hydrolyzed copolymers of vinyl acetate with isopropenyl acetatewith a degree of hydrolysis of from 95 to 100 mol %.
 9. The process ofclaim 1, further comprising combining the dried additive with one ormore water-redispersible polymer powders derived from at least onemonomer selected from the group consisting of vinyl esters of unbranchedor branched alkanecarboxylic acids having from 1 to 15 carbon atoms,methacrylic esters and acrylic esters of alcohols having from 1 to 15carbon atoms, vinylaromatics, olefins, dienes and vinyl halides.
 10. Theprocess of claim 1, wherein component b1) is present in an amount of10-40 weight percent.
 11. The process of claim 1, wherein component b2)is present in an amount of 0.1 to 20 weight percent.
 12. The process ofclaim 1, wherein component b2) is present in an amount of from 1 to 10weight percent.
 13. The process of claim 1, wherein drying isaccomplished by spray drying.
 14. A hydrophobicizing additive, preparedby the process of claim
 1. 15. A hydrophobicizing additive, prepared bythe process of claim
 2. 16. A hydrophobicizing additive, prepared by theprocess of claim
 3. 17. A hydrophobicizing additive, prepared by theprocess of claim
 4. 18. A hydrophobicizing additive, prepared by theprocess of claim
 5. 19. In a construction chemistry product wherein ahydrophobicizing additive is employed, the improvement comprisingselecting as at least one hydrophobicizing additive, an additive ofclaim
 14. 20. The construction chemistry product of claim 19, whichcontains at least one hydraulically settble inorganic binder.
 21. Theconstruction chemistry product of claim 19, which is one of constructionadhesive, render, troweling compound, floor-filling composition,leveling composition, sealing slurry, jointing mortars or paints. 22.The construction chemistry product of claim 19, which least oneinorganic binder is selected from the group consisting of cement,waterglass, gypsum, and lime.